The invention provides reaction mixtures comprising polyols, triglycerides, base initiators and phase-transfer catalysts for performing transesterification reactions. The reaction product comprises a mixture rich in polyol monoesters and polyol diesters.
Large-scale transesterification of triglycerides with polyols is performed commercially. In particular, mixtures rich in polyol fatty acid monoesters and polyol fatty acid diesters, such as monoglycerides and diglycerides are commercially produced in quantities of greater than 50 million pounds per year, primarily by transesterification of triglycerides, such as fatty triglycerides, with polyols, such as glycerol and propylene glycol. Triglycerides are reacted with glycerol in the presence of a glycerolysis catalyst to provide a product that is a mixture of monoglycerides, 1,2-diglycerides, 1,3-diglycerides, glycerol, and triglycerides. A particularly useful raw material for such large volume commercial transesterifications is a mixture of fatty triglycerides, obtained from agricultural sources such as vegetable oil or animal fat. Vegetable oil triglycerides and animal fat triglycerides are inexpensive and readily available. Products rich in polyol fatty acid monoesters and polyol fatty acid diesters obtained from the transesterification of vegetable oil triglycerides with polyols, such as glycerol and propylene glycol are particularly useful for food applications, such as food emulsifiers for margarine and ice cream. Other useful transesterifications of triglycerides with polyols use tributyrin or triacetin as the triglyceride.
Mixtures rich in polyol acid monoesters and polyol acid diesters may also be produced by transesterification of fatty monoacid lower alkyl esters with polyols, such as methyl esters of fatty monoacids. However, the cost of fatty monoacid lower alkyl esters as a raw material for production of polyol fatty acid monoesters and polyol fatty acid diesters is higher than that of using fatty triglyceride as a raw material. Fatty monoacid lower alkyl esters are commercially produced by alcoholysis of fatty triglycerides using lower alcohols, such as methanol and ethanol. Alcoholysis represents an added step with added cost as compared to reacting the polyol directly with fatty triglyceride.
There is a need in the art for new and improved methods of producing polyol acid monoesters and polyol acid diesters. The invention is directed to this, as well as other, important ends.
The invention provides an improved process for performing transesterification of triglycerides with polyols, and more particularly, provides an improved process for performing transesterification of triglycerides with polyols in the presence of a base initiator and a phase transfer catalyst to produce mixtures rich in polyol monoesters and polyol diesters. In one embodiment, the invention provides an improved process for performing transesterification of fatty triglycerides with polyols in the presence of a base initiator and a phase transfer catalyst to produce mixtures rich in polyol fatty acid monoesters and polyol fatty acid diesters.
The invention also provides reaction mixtures of phase transfer catalysts, triglycerides, base initiators and polyols for use in transesterification reactions at low temperatures to produce mixtures rich in polyol monoesters and polyol diesters. In one embodiment, the invention provides reaction mixtures of phase transfer catalysts, fatty triglycerides, base initiators and glycerol or propylene glycol for use in transesterification reactions at low temperatures or low heat histories to produce mixtures rich in polyol fatty acid monoesters and polyol fatty acid diesters. In other embodiments, the transesterification reactions can avoid the use of highly processed fatty monoacid lower alkyl esters as a raw material.
These and other aspects of the invention are described in more detail below.